Milling-cutter.



H. E. EBERHARDT.

MILLING CUTTER.

APPLICATION men NOV-1,1913.

Patented June 1, 1915.

FIG. fl.

"HE NORRIS PETERS CO. PHOTO-LITHQ. WASHINGTON. D, C.

HENRY E. EBERHARDT, OF NEWARK, NEW JERSEY, ASSIGNOR 'IO NEWARK GEARCUTTING MACHINE JERSEY,

Specification of Letters Patent.

Patented June 1, 1915.

Application filed November 1, 1913. Serial No. 798,635.

7 To all whom it may concern Be it known that I, HENRY E. EBER- HARDT, acitizen of the United States, and a resident of Newark, in the county ofEssex and State of New Jersey, have invented certain new and usefulImprovements in Milling-Cutters, of which the following is aspecification.

The invention relates to cutters, more particularly to rotary millingcutters or hobs,

and which are adapted to befixedly secured to a rotatable arbor anddriven thereby. In

cutters of this type, as heretofore constructfrom the key and thus tocause the teeth of the cutter on that side to be some two onethousandthsof an inch out of concentricity. Moreover, when the cutter is in actionit is crowded away still farther from the said key and approximately butone-third of the teeth do the greater part of the work. These naturallybecome dull sooner than the rest and sharpening of the cutter isrequired before all of the teeth are equally worn.

It is the object of the present invention to so construct the cutterthat it may be mounted in manner to afford greater cutter efficiencybetween sharpenings, that is to say, to enable the cutter to be in usefor a longer period before requiring resharpening, it being possiblewith the improved cutter to obtain substantially two-thirds more workout of the cutter than heretofore.

The nature of the invention will be best understood when described inconnection with the accompanying drawings, in which- Figure l is a planof the cutter and a portion of arbor upon which it is mounted. Fig. 2 isan elevation thereof, the arbor and key being shown in section.

Similar characters of reference designate corresponding parts throughoutthe several vlews.

Referring to the drawings, 10 designates an arbor rotated in anysuitable manner and provided with a key 11 by means of which a cutter 12may be driven, said cutter being provided with a central opening 13through which the arbor is fitted and the key 11 being adapted to engagea keyway 14, as is well understood. Instead of providing but one keyway,as is the usual practice, a plurality of keyways 14 are provided and arearranged symmetrically to extend outwardly from the central opening 13.In the present instance, I have shown three such keyways arrangedsubstantially 120 apart; and, furthermore, suitable characters such asthe numbers 1, 2, 3, shown, are provided upon the face of the cutter hubto differentiate the respective keyways, the numbers preferably beingarranged consecutively in the di rection of cutting. Thus when one-thirdof the teeth have become dulled with the cutter mounted upon the arborin the position 1, the cutter is removed from the arbor and advancedrelatively thereto 120 into position 2 and the keyway 14: correspondingto this position fitted to the key 11. A set of comparatively sharpteeth will then again be brought into action; and when these in turn aredull, the cutter is shifted to the third position and thereafter thecutter as a whole will require resharpening. Had the cutter but onekeyway, as in the usual practice, as soon as the set of high teeth weredull, the entire cutter including the sharp as well as the dull teethwould require regrinding, resulting in loss of time as well as of cuttermaterial.

'I claim 1. The combination with a rotary arbor and a single keythereon, of a milling cutter having a circular hole in the centerthereof and provided with a plurality of keyways for said key wherebythe cutter may be driven by said arbor.

2. The combination with a rotary arbor and a key thereon, of a millingcutter provided With a circular central hole for the Signed at Newark,in the county of Essex,

said arbor and with three keyways extendand State of New Jersey, this31st day of ing outwardly therefrom and substantially October, A. D.1913.

120 apart whereby the cutter may bedriven- HENRY E; EBERHARDT. by saidarbor, the said cutter being provided Witnesses:

at the respective keywa-ys With suitable IIENRI J. EBERHARDT,

characters to differentiate the said keyways. FRE F. SQnUETz,

Copies of this patent may be obtained for fiye cents each, by addressingthe Commissioner of Patents. Washington, .D. 0; r V

